Using LVM Snapshot to Backup MySQL

1. 数据库全局读锁
   flush tables with read lock;
2. LVM 快照
   lvcreate -L 500M -s -n mysql-snap /dev/datavg/mysql-snap
   mysql -uroot -p'Jove@123' -e 'show master status' > /backup/date +%F_position.log
3. 释放全局读锁（关闭全局锁会话时，锁将自动失效）
   unlock tables;
4. 挂载快照卷（只读）
5. 从快照卷中复制数据（cp/tar）
6. 卸载并删除快照卷

#! /bin/bash
# LVM Snapshot for mysql backup

backup_dir=/backup/`date +%F`
[ -d $backup_dir ] || mkdir -p $backup_dir

echo "FLUSH TABLES WITH READ LOCK; \
SYSTEM lvcreate -L 500M -s -n mysql-snap /dev/datavg/mysql; \
SHOW MASTER STATUS; \
UNLOCK TABLES;" | mysql -uroot -p'welcome@123' > $backup_dir/backup.log

# nouuid, for xfs
mount -o ro,nouuid /dev/datavg/mysql-snap /mnt

rsync -a /mnt/ $backup_dir

if [ $? -eq 0]; then
  umount /mnt
  lvremove -f /dev/datavg/mysql-snap
fi